Lifting eyebolt assembly

ABSTRACT

A lifting eyebolt assembly for engagement between a workpiece to be lifted and a lifting device includes cylindrical collar that is held in place against the workpiece by a threaded fastener. A load-bearing ring is threadedly engaged to the collar to enclose the collar and the fastener. The load-bearing ring includes an eye portion for engaging the lifting device and a base portion for engaging the collar.

This application is a continuation of application Ser. No. 07/569,922,filed Aug. 20, 1990 now U.S. Pat. No. 5,054,982.

BACKGROUND OF THE INVENTION

This invention relates generally to a lifting eyebolt for connectionbetween a workpiece to be lifted and a lifting device, such as a hoist.

A lifting device is normally attached to an eyebolt, which in turn isnormally secured to the workpiece or load to be lifted. Becauseworkpieces come in various shapes and usually leave little or no choiceas to where a lifting eyebolt can be attached, the eyebolts areregularly subjected to forces at odd angles that often result in largebending and shear stresses. These forces often mandate the use of anoversized eyebolt. However, the use of an oversize bolt may requiredrilling and tapping a new, larger hole in the workpiece to be lifted.

A lifting eyebolt is most efficient when the force exerted on theeyebolt lies in the plane defined by the eye. This effectivenessdeteriorates rapidly as force is applied outside the plane of the eye.Another problem of typical eyebolts is their tendency to bend at theinterface to the workpiece. This bending can stress the eyebolt until itshears at the attachment face of the workpiece.

An improvement over existing eyebolts is desirable which allows theeyebolt to be attached securely to a workpiece in a way that ensuresthat the force from the lifting device can always be made to lie in theplane of the eye. This flexibility will allow the efficient use ofproperly sized eyebolts and will also result in a prolonged working lifefor each individual eyebolt. It is also desirable to provide an improvedeyebolt assembly that prevents or restricts bending of the eyebolt atthe interface to the workpiece.

SUMMARY OF THE INVENTION

One embodiment of the lifting eyebolt assembly comprises a cylindricalcollar that is held in place against the workpiece by a fastener. Thebase portion of a load-bearing ring includes a threaded bore to engagean outer threaded surface of the cylindrical collar. The collar is freeto rotate about the fastener, at least until the fastener is tightenedto the workpiece. The load-bearing ring is shaped to provide means toaccess the fastener after the collar and fastener have been receivedinto the base portion of the load-bearing ring. The load-bearing ringcan be secured to the collar, and in turn to the workpiece, so that theplane defined by the eye is in any desired orientation around the axisof the fastener.

In another embodiment of the invention, the eye portion of theload-bearing ring is offset from the axis of the fastener. The collar isnot threaded on its outer surface but instead has a flange around itsupper rim, which serves to keep the base portion of the ring in place.The base portion includes an unthreaded bore that is slightly largerthan the outer diameter of the body of the collar but smaller than thecollar flange. In this embodiment, when the fastener has secured thecollar to the workpiece, the load-bearing ring remains free to rotateabout the collar and about the axis defined by the fastener.

In another embodiment of the invention, a load-bearing ring is pivotallyattached to a housing, which housing is threadedly secured to acylindrical collar. Like the previous embodiment, the collar is held inplace against the workpiece by a fastener. In this embodiment, thehousing is shaped to provide access to the fastener after the fastenerand collar have been received into the housing. The pivotal axis of theload-bearing ring is made perpendicular to the axis defined by thefastener. In this embodiment, the plane of the load-bearing ring can beoriented prior to completely securing the fastener to the workpiece. Thepivoting ring provides a second degree of rotational freedom, whichfurther eliminates potentially damaging torques on the assembly.

An object of this invention is to provide a simple, economical andrelatively lightweight alternative to conventional lifting eyebolts,which can be quickly adapted to a variety of load lifting situations.The new design allows the eyebolt assembly to be quickly and properlyaligned with the line of pull from the lifting device in a way that bestutilizes the strength of the eyebolt.

Another object is to decrease the risk of deforming or shearing theeyebolt at the interface to the workpiece. This invention reduces manyunnecessary stresses that otherwise plague conventional eyebolts. Afurther object is to eliminate the need to drill and tap a larger holein the workpiece to accommodate a larger eyebolt. Other objects andbenefits of the invention will become apparent from the followingdescription and accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front cross-sectional view of a lifting eyebolt assembly ofthis invention attached to a workpiece, with two offset eye embodimentsshown by phantom lines;

FIG. 1A is fragmentary front cross-sectional front view of a liftingeyebolt assembly as viewed in FIG. 1 with the substitution of a flangedcollar;

FIG. 2 is a front cross-sectional view of a swiveling offset eyeembodiment of the lifting eyebolt assembly of the invention attached toa workpiece;

FIG. 3 is a partial front cross-sectional view of a pivoting embodimentof a lifting eyebolt assembly of the invention attached to a workpiece;

FIG. 4 is a side elevational view of the lifting eyebolt assembly shownin FIG. 3.

FIG. 5 is a front cross-sectional view of a lifting eyebolt assembly ofanother embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiment illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended, such alterations and furthermodifications in the illustrated device, and such further applicationsof the principles of the invention as illustrated therein beingcontemplated as would normally occur to one skilled in the art to whichthe invention relates.

One embodiment of the present invention is illustrated in FIG. 1. Alifting eyebolt assembly 9 includes a load-bearing ring 10 which isremovably attached to a workpiece 11 by a fastener 12. The fastener 12,in one specific embodiment, is an allen head screw, although some otherconventional fastener may be used. A collar 13 is provided having athreaded outer surface 14 and a longitudinal bore 15 therethrough. Thebore 15 is sized to receive fastener 12 therethrough in a way thatallows the collar to freely rotate about axis 16, at least until thefastener is fully tightened to the workpiece.

The load-bearing ring 10 includes an eye portion 17 and a base portion18. The eye portion 17 has an opening 19 to engage the shackle or hook(not shown) of a lifting device. Two offset eye embodiments are shown inphantom in FIG. 1. In one embodiment, the eye portion 17' lies in thesame plane as eye 17 but is oriented at an angle to the axis 16 of thefastener 12. In the other embodiment, the eye portion 17" is orientedwith its plane at right angles to the plane of eye 17 and generallyparallel to the face of the workpiece.

The base portion 18 defines a cavity 21 large enough to accommodate thecollar 13 and the head 20 of fastener 12. The cavity 21 is threaded onits inner surface 22 in order to engage the threaded outer surface 14 ofcollar 13. In one embodiment, the load-bearing ring 10, which ispreferably made from forged steel to ensure proper strength, includes anaccess hole 23 between eye opening 19 and cavity 21. The access hole 23provides passage for an allen wrench or other tool (not shown) to eitherloosen or tighten fastener 12, in this case an allen screw, by engagingrecess 24 in the head 20 of the fastener 12.

The lifting eyebolt assembly 9 can be assembled by first insertingfastener 12 into collar 13. If the fastener is a screw, the fastener 12is threaded into the workpiece until the collar 13 is held tightlyagainst the workpiece. The base portion 18 of the load-bearing ring 10can be threaded upon the collar 13 until tight and then loosenedapproximately 1/2 turn to avoid stressing the fastener threads. When theeye portion 17 of the load-bearing ring 10 is connected to the liftingdevice, the plane defined by the eye portion 17 will automatically alignitself with the direction of pull. Thus, the full strength of theeyebolt is utilized in a way that reduces potentially harmful shear andbending stresses.

In another manner of assembly, the components of the lifting eyeboltassembly 9 are pre-assembled but not yet attached to a workpiece. Thelifting ring base portion 18 can be threaded onto the collar 13 with thefastener 12 trapped within cavity 21. The base portion can be threadedonto the collar until the bottom surfaces of the base portion and thecollar are generally flush. A fastener tool, in this case an allenwrench (not shown), can be inserted through access hole 23 to engage therecess 24 of head 20 of fastener 12. The entire unit is then rotated andthreaded into the workpiece.

In one specific manner of assembly, the unit is threaded into theworkpiece until hand-tight. The eye portion 17 of the load-bearing ringcan then be rotated about the fastener axis 16 to align the plane of theeye portion 17 with the direction of pull of the lifting device.Finally, the allen wrench can be reinserted into access hole 23 in orderto securely tighten the fastener 12 to the workpiece. This arrangementallows the vertical plane defined by eye portion 17 to be placed in anydesired orientation about axis 16 before finally being tightened into afixed position with respect to the workpiece. Thus, the load-bearingring 10 can always be oriented properly with respect to the line of pullfrom a lifting device so as to fully utilize the strength of theeyebolt.

FIG. 1A shows a variation of the embodiment disclosed in FIG. 1 in whicha collar 13' is modified from the collar 13 in FIG. 1 to include aflange 13a'. The load-bearing ring 10 and fastener 12 are configuredsubstantially as previously described. The base portion 18 of the ring10 rests on the top surface of the flange 13a', while the bottom surfaceof the flange abuts the face of the workpiece 11. The flange 13a' bearsmost of the forces exerted on the assembly 9', rather than the fastener12. The flange 13a' includes a bore 13b' therethrough. The base portion18 can includes a threaded bore 18b aligned with bore 13b'. A set screw25 can be inserted through bore 13b' and threaded into bore 18b beforethe complete lifting eyebolt assembly 9' is attached to a workpiece.

It is understood that there are numerous other equivalent ways toprevent the load-bearing ring 10 from rotating with respect to collar13'. For instance, the screw 25 may be replaced by a dowel pin orsimilar means to fix the ring 10 against rotation relative to the collar13' so that the assembly 9' can be more easily secured to a workpiecewithout concern that the load-bearing ring will loosen from the collar.

An eyebolt assembly 26 of another embodiment of the present invention,as illustrated in FIG. 2, incorporates a swiveling offset eye. Aload-bearing ring 30 is removably attached to a workpiece 31 by afastener 32, in the illustrated case an allen screw. A collar 33 definesa longitudinal bore 34 having an inner diameter that allows the shaft 35of the fastener to pass freely therethrough. The collar 33 includes acylindrical body 36 with an upper flange 37 of larger outer diameterthan the body.

The lower face of body 36 of collar 33 is received within a recess 38formed in a base plate 39. The base plate 39 defines a hole 40 that hasa diameter sufficient to allow the shaft 35 of the screw to pass freelytherethrough, similar to the longitudinal bore 34 of the collar. Thebase plate 39 also includes a bore 29 which is sized to receive pin 27therethrough. A corresponding bore 28 in the collar 33 can be alignedwith bore 29 when the collar is situated within recess 38 of base plate39. When engaged, the pin 27 prevents the base plate 39 from rotatingwith respect to collar 33. If desired, the body 36 of the collar 33could also be made to be threadedly attached or otherwise secured tobase plate 39 in order to keep the complete assembly in one piece whennot attached to a workpiece.

The load-bearing ring 30 consists of an eye portion 41 and a baseportion 42, and is preferably made from forged steel to ensure adequatestrength. The base portion 42 includes a bore 43, which is stepped froma first inner diameter 44 down to a second inner diameter 45 creating aninternal shoulder 48. The first diameter 44 is made slightly larger thanthe flange 37 of the collar 33, while the second diameter 45 is slightlylarger than the outer diameter of the body 36 of the collar 33. Theload-bearing ring 30 is prevented from escaping from the lifting eyeboltassembly 29 because the shoulder 48 is retained under the flange 37 ofcollar 33.

The complete unit can be assembled by first inserting fastener 32through the longitudinal bore 34 of collar 33. These two pieces are thenreceived by the base portion 42 of the load-bearing ring 30 so that theflange 37 of collar 33 rests upon shoulder 48. The base plate 39receives the fastener 32 and the collar 33 at bore 40 and recess 38,respectively. The lifting eyebolt assembly 26 is then secured to theworkpiece 31 by tightening the fastener 32 to the workpiece. In thisembodiment, the plane defined by the eye 46 automatically aligns withthe direction of pull from the lifting device, since the base portion 42remains free to swivel between flange 37 and base plate 39 about axis47, after the fastener is fully tightened to the workpiece 31.

FIGS. 3 and 4 show another pivoting eye embodiment of this invention.The assembly 49 includes a load-bearing ring 50 removably attached to aworkpiece 51 by a fastener 52, in this case an allen head screw. Acollar 53 is provided having a threaded outer surface 54 and alongitudinal bore 55 therethrough. The bore 55 is sized to receive theshaft 56 of fastener 52 therethrough in a way that allows the collar tofreely rotate about axis 57 until the collar is tightened to theworkpiece 51 by the fastener.

The assembly also includes a housing 58 which defines a cavity 59 largeenough to accommodate the head 60 of fastener 52. The cavity 59 isthreaded at its inner surface 61 to engage the threaded outer surface 54of collar 53. The housing 58 also includes an access hole 62 abovecavity 59. The access hole 62 provides passage for an allen wrench orother appropriate tool (not shown) to engage recess 63 of the head 60 ofthe fastener to loosen or tighten fastener 52.

The load-bearing ring 50 includes of an eye portion 64 and a pivotportion 65. The pivot portion 65 includes a bore 66 therethrough that isadapted to be rotatably mounted upon an axle 67. The axle 67 is carriedbetween two upright support arms 68 and 69 that form a part of housing58, which is best shown in FIG. 4. Axle hubs 70 and 71 are attached atrespective ends of the axle 67 in order to keep the axle from escapingthe upright support arms 68 and 69.

The housing 58 may also include a threaded bore 72 that opens to cavity59. After the housing 58 receives the fastener 52 and collar 53 incavity 59, the housing can be restrained against rotation with respectto collar 53 by tightening a set screw 73 in threaded bore 72 againstthe outer surface 54 of the collar. A similar set screw may also be usedin the embodiment of FIG. 1 to fix the base portion 18 to the collar 13.

Like the embodiment shown in FIG. 1, this embodiment would allow aworkman to align the plane defined by the eye 72 with the direction ofpull from the lifting device before the lifting eyebolt assembly 49 issecured to the workpiece. Furthermore, the pivot feature of this versionallows the load-bearing ring 50 to optimally align itself with thedirection of pull so as to fully utilize the strength of the eyebolt.

Another embodiment of the invention is illustrated in FIG. 5 in which alifting eyebolt assembly 80 is attached to a workpiece 88. The assembly80 includes an eyebolt 81 which can be of standard construction, albeitlarger than the eyebolt that would normally be used to lift theworkpiece in the absence of the present eyebolt assembly. The eyebolt 81has an eye portion 82 for engagement with a lifting device and athreaded stem 83, which stem would normally be threaded into theworkpiece. However, in the present invention, the eyebolt 81 isconnected to the workpiece 88 through a cap screw 85 and adaptor 90.

The cap screw 85 includes a threaded portion 86 for engagement with athreaded bore in the workpiece 88. In the preferred embodiment, the capscrew threaded portion 86 is sized to match the standard tapped holes inthe workpiece. The threaded stem 83 of the eyebolt has a larger diameterthan the threaded portion 86 of the cap screw 85 to handle greaterforces exerted on the eyebolt by lifting the workpiece.

The adaptor 90 is a generally cylindrical body having a boretherethrough. The lower bore portion 91 of the bore has a diametersufficient to accept the threaded portion 86 of the cap screw. However,the diameter of this lower bore portion 91 is smaller than the diameterof the head 87 of the cap screw 85 so the screw can be used to attachthe adaptor to the workpiece. The cap screw head 87 contacts a shoulder93 formed by the lower bore portion. The adaptor contacts the workpiece88 at its mounting face 94 and is firmly affixed to the workpiece bytightening the cap screw 85 to the workpiece.

The adaptor 90 also includes an upper bore portion 92 that has adiameter larger than the cap screw 85 so the screw can be insertedtherethrough. The upper bore portion 92 is threaded of at least some ofits length to match the threaded stem 83 of the eyebolt. After theadaptor 90 has been mounted to the workpiece 88 by the cap screw 85, theeyebolt 81 can be threaded into the upper bore portion 92 until thethread engagement is tight, and then preferably backed off about 1/4turn. The eyebolt stem 83 in FIG. 5 is shown contacting the head 87 ofthe cap screw 85. Alternatively, the upper bore portion 92 of theadaptor can be long enough so that the eyebolt does not contact the capscrew.

The eyebolt assembly 80 of this embodiment permits the use of a largerdiameter eyebolt, such as eyebolt 81, without the necessity of drillingand tapping a larger hole in the workpiece 88. Moreover, the adaptor 90increases the contact area at its mounting face 94 over the contact areaof typical eyebolts used in a conventional manner. One benefit is thatlarger eyebolts can be used to lift heavier loads and withstand greaterbending moments, while distributing these loads over a larger area onthe face of the workpiece.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character. For instance, the liftingeyebolt assembly can be made to any size depending on the strengthrequired due the size of the workpiece. It being understood that onlythe preferred embodiments have been shown and described and that allchanges and modifications that come within the spirit of the inventionare desired to be protected.

What is claimed is:
 1. A lifting eyebolt assembly for engagement betweena workpiece to be lifted and a lifting device, the workpiece having athreaded bore, the assembly comprising:a fastener having a head portionand a threaded portion for threaded engagement with the threaded bore ofthe workpiece; an eyebolt having an eye portion for connection to thelifting device and a threaded stem portion; an adaptor having a boreextending therethrough, said bore having a first portion of a firstdiameter and a second portion of a larger second diameter, and furtherhaving a shoulder defined between said first portion and said secondportion, wherein said first diameter is sized to accept said threadedportion of said fastener therethrough so that said head portion contactssaid shoulder; further wherein said second portion of said bore isinternally threaded to engage said threaded stem portion of said eyeboltfor engaging said eyebolt to said adaptor when said fastener is fastenedto the workpiece; and said adaptor further having a mounting faceadjacent said first diameter for contacting the workpiece when saidfastener is engaged in the threaded bore of the workpiece.
 2. Thelifting eyebolt assembly of claim 1, wherein said stem portion of saideyebolt is sufficiently long relative to the length of said secondportion of said bore so that said stem portion contacts said headportion of said fastener when said head portion and said stem portionare within said second portion of said bore.
 3. A lifting eyeboltassembly for engagement between a workpiece to be lifted and a liftingdevice, the workpiece having a threaded bore, the assembly comprising:afastener having a head portion and a threaded portion for threadedengagement with the threaded bore of the workpiece; an eyebolt having aneye portion for connection to the lifting device and an integral baseportion; an adaptor body defining a bore therethrough said bore having afirst portion of a first diameter and a second portion of a largersecond diameter, and further having a shoulder defined between saidfirst portion and said second portion, wherein said second diameter issized to accept said head portion and said first diameter is sized toaccept said threaded portion of said fastener therethrough so that saidhead portion contacts said shoulder, said adaptor further having amounting face adjacent said first diameter for contacting the workpiecewhen said fastener is engaged in the threaded bore of the workpiece; andthreaded means between said adaptor body and said base portion of saideyebolt for threadedly engaging said eyebolt to said adaptor body totrap said head of said fastener within said second portion of said bore.4. The lifting eyebolt assembly of claim 3, wherein said threaded meansincludes:external threads on said integral base portion; and matinginternal threads in said second portion of said bore through saidadaptor body.